What term refers to the presence of air in the biliary tract?

The term that refers to the presence of air in the biliary tract is "pneumobilia." This condition typically arises from various etiologies, such as an abnormal connection between the biliary tree and the gastrointestinal tract, for instance, due to a fistula or after surgical procedures that involve the liver or biliary system.

In imaging studies, particularly ultrasound, the visualization of air within the biliary system can indicate pathology and requires further investigation to determine the underlying cause. Pneumobilia can manifest as bright echoes within the biliary ducts, providing insights into potential complications or infections.

The other terms do not relate to air within the biliary system specifically. Pneumothorax refers to the presence of air in the pleural space, pneumoperitoneum involves air in the peritoneal cavity, and pneumocystitis would refer to air within a cyst, which does not apply to the biliary tract. Understanding these terms helps clarify the diagnosis and management of various abdominal conditions.